[v2,6/6] dax: bdev_direct_access() may sleep
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Message ID 1435934443-17090-7-git-send-email-matthew.r.wilcox@intel.com
State New
Headers show

Commit Message

Wilcox, Matthew R July 3, 2015, 2:40 p.m. UTC
The brd driver is the only in-tree driver that may sleep currently.
After some discussion on linux-fsdevel, we decided that any driver
may choose to sleep in its ->direct_access method.  To ensure that all
callers of bdev_direct_access() are prepared for this, add a call
to might_sleep().

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
---
 fs/block_dev.c | 6 ++++++
 1 file changed, 6 insertions(+)

Patch
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diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0bb2993..1982437 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -446,6 +446,12 @@  long bdev_direct_access(struct block_device *bdev, sector_t sector,
 	long avail;
 	const struct block_device_operations *ops = bdev->bd_disk->fops;
 
+	/*
+	 * The device driver is allowed to sleep, in order to make the
+	 * memory directly accessible.
+	 */
+	might_sleep();
+
 	if (size < 0)
 		return size;
 	if (!ops->direct_access)